diff --git a/toolbox/swapon.c b/toolbox/swapon.c
new file mode 100644
index 0000000..afa6868
--- /dev/null
+++ b/toolbox/swapon.c
@@ -0,0 +1,73 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <asm/page.h>
+#include <sys/swap.h>
+
+/* XXX These need to be obtained from kernel headers. See b/9336527 */
+#define SWAP_FLAG_PREFER        0x8000
+#define SWAP_FLAG_PRIO_MASK     0x7fff
+#define SWAP_FLAG_PRIO_SHIFT    0
+#define SWAP_FLAG_DISCARD       0x10000
+
+void usage(char *name)
+{
+    fprintf(stderr, "Usage: %s [-p prio] <filename>\n"
+        "        prio must be between 0 and %d\n", name, SWAP_FLAG_PRIO_MASK);
+}
+
+int parse_prio(char *prio_str)
+{
+    unsigned long p = strtoul(prio_str, NULL, 10);
+
+    return (p > SWAP_FLAG_PRIO_MASK)? -1 : (int)p;
+}
+
+int swapon_main(int argc, char **argv)
+{
+    int err = 0;
+    int flags = 0;
+    int prio;
+
+    opterr = 0;
+    do {
+        int c = getopt(argc, argv, "hp:");
+        if (c == -1)
+            break;
+
+        switch (c) {
+            case 'p':
+                if (optarg != NULL)
+                    prio = parse_prio(optarg);
+                else
+                    prio = -1;
+
+                if (prio < 0) {
+                    usage(argv[0]);
+                    return -EINVAL;
+                }
+                flags |= SWAP_FLAG_PREFER;
+                flags |= (prio << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK;
+                break;
+            case 'h':
+                usage(argv[0]);
+                return 0;
+            case '?':
+                fprintf(stderr, "unknown option: %c\n", optopt);
+                return -EINVAL;
+        }
+    } while (1);
+
+    if (optind != argc - 1) {
+        usage(argv[0]);
+        return -EINVAL;
+    }
+
+    err = swapon(argv[argc - 1], flags);
+    if (err) {
+        fprintf(stderr, "swapon failed for %s\n", argv[argc - 1]);
+    }
+
+    return err;
+}